A direct modeling approach to momentum, heat and mass exchange at the ocean-atmosphere interface at high wind speed

高风速下海洋-大气界面动量、热量和质量交换的直接建模方法

• 批准号: 2318816
• 负责人: Luc Deike
• 金额: $ 84.47万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-10-01 至 2026-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2318816&HistoricalAwards=false
• 关键词: direct; modeling; approach; momentum; heat

A better understanding of exchange of momentum, heat, and mass at the ocean-atmosphere interface at very high wind speed is necessary to better predict extreme weather events, which have dramatic impact on human activities, such as tropical cyclone intensification. Given the complexity of these two-phase turbulent flows, modeling tools are extremely valuable to unravel the detailed physical mechanisms. This research will provide a novel computational framework for fully coupled air-water simulations at high wind speed, including breaking waves, turbulent wind, droplet generation and their influence on the heat and mass exchange in the turbulent wave boundary layer. The initial work on the small-scale dynamics of individual breaking waves and droplet evolution will feed into a larger-scale model able to resolve the flows that provide the forcing context for the small-scale model. This comprehensive approach will lead to a general improvement in simplified models and parameterization, that can be implemented and tested in a wide range of numerical tools, from high resolution models to larger scale Earth system models, leading to improvement in climate and weather forecast. This project will expose undergraduate and graduate students at Princeton to critical environmental challenges that require research on fundamental multi-phase flows, and promote the use of open-source methods, through workshop and teaching activities.The large range of scales involved in air-sea interaction will be split into two sets of more tractable problems. The first will consider droplet evaporation in the air, fully resolving droplet ejection and heat exchange with the surrounding air for wind-wave breaking dynamics forced by turbulent boundary layer. Such high-fidelity simulations will span scales from 100 microns to 1m and focus on understanding the small-scale coupling between high wind forced turbulence close to the water surface and droplets, directly solving for heat and mass exchange, waves and droplets processes and the coupling of heat and momentum exchange at high wind speed. The models developed for these small-scale processes will be integrated into a multi-layer numerical framework, akin to large eddy simulations. Such simulations will be able to resolve realistic breaking wave statistics spanning scales from 1m to 1km, allowing to represent the outer scales of the turbulent flow. Analysis of the heat and momentum budget will help understand current uncertainties in bulk formulation and may lead to new parameterizations for the heat and drag coefficient applicable to larger scale models used for tropical cyclone intensification studies.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

为了更好地预测极端天气事件，需要更好地了解在极高风速下海洋-大气界面上的动量、热量和质量交换，极端天气事件对人类活动具有重大影响，如热带气旋增强。考虑到这些两相湍流的复杂性，建模工具对于揭示详细的物理机制是非常有价值的。这项研究将为高风速下完全耦合的气-水模拟提供一种新的计算框架，包括破碎波、湍流风、液滴的产生及其对湍流波边界层内热质交换的影响。关于单个破碎波的小尺度动力学和液滴演化的初步工作将提供给一个能够解决为小尺度模型提供强迫背景的流动的更大尺度模型。这一综合办法将导致简化模型和参数的普遍改进，可在从高分辨率模型到更大比例的地球系统模型的各种数值工具中实施和测试，从而改进气候和天气预报。这个项目将使普林斯顿大学的本科生和研究生接触到关键的环境挑战，这些挑战需要研究基本的多相流，并通过研讨会和教学活动促进开源方法的使用。涉及海-气相互作用的大范围范围将被分成两组更容易处理的问题。第一种方法考虑了液滴在空气中的蒸发，完全解决了湍流边界层强迫风浪破碎动力学中的液滴抛射和与周围空气的换热问题。这种高保真模拟将跨越从100微米到1米的尺度，重点了解接近水面的大风强迫湍流与液滴之间的小尺度耦合，直接求解热质交换、波和液滴过程以及高速风速下的热量和动量交换耦合。为这些小规模过程开发的模型将被集成到一个类似于大涡模拟的多层数值框架中。这样的模拟将能够解决从1米到1公里尺度上的现实破碎波统计，从而能够表示湍流的外部尺度。对热量和动量预算的分析将有助于理解当前批量公式中的不确定性，并可能导致适用于热带气旋强化研究的更大尺度模式的热量和阻力系数的新参数。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。